This invention relates to an improved process for the production of 2-nitrobutylmorpholine.
More particularly, this invention relates to an improved process for the production of 2-nitrobutylmorpholine by reacting 1-nitropropane, morpholine and formaldehyde.
The prior known processes for the production of 2-nitrobutylmorpholine, Senkus, U.S. Pat. No. 2,474,791 teach the production of 2-nitroisobutylmorpholine from the reaction of a nitroalcohol and a cyclic secondary amine (2-nitro-2-methyl-1-propanol and morpholine). The second process taught by Senkus is the reaction of formaldehyde with the cyclic secondary amine (morpholine) which in turn is reacted with a secondary nitroparaffin (2-nitropropane). A variation of the first method as taught by Senkus is the reaction of formaldehyde with the nitroparaffin (2-nitropropane) to produce the nitroalcohol which in turn is reacted with the cyclic secondary amine (morpholine) which process is hereinafter called the morpholine addition method.
A by-product from the reaction forming 2-nitrobutylmorpholine from 1-nitropropane, formaldehyde and morpholine is 2-nitro-1-butanol. 2-Nitro-1-butanol is difficult to separate from the 2-nitrobutylmorpholine product and as a nitroalcohol can react violently with bases such as morpholine. The 2-nitro-1-butanol formed contaminates and reduces the yield and purity of 2-nitrobutylmorpholine. Another disadvantage inherent in the prior processes is that they require excess 1-nitropropane and morpholine to drive the reaction to completion. Generally a 20% excess 1-nitropropane and 1% excess morpholine over formaldehyde are required. The use of such excesses is uneconomical and the excess of both reactants adds to the contamination of the product. The use of excess reactants reduces the efficiency of the process in that more reactants are required to drive the reaction to completion than actually react and effort is needed to separate the reactants from the finished products. The prior processes require strict controls during the reaction in order to produce 2-nitrobutylmorpholine efficiently. In the morpholine addition process strict controls are maintained on the addition of the morpholine. Longer addition times than three hours or interruptions during the addition step produces more of the by-product 2-nitro-1-butanol.